It's an act of desperation. Pointing to the USA as meddlers in Iranian affairs had gne a long way to keeping the establishment in power over the last 8 years. Before W. declared Iran part of the 'Axis of Evil', they actually had a reformer in office who butted heads with the clergy all the time. That all changed in 2001. Now, the clergy need a demon more than ever and Obama did the most annoying thing he possibly could; Be reasonable.
Ya rly. Not to mention the U.S. and U.K. (also a target of meddling accusations) are convenient scapegoats thanks to operation Ajax.